Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
Möbius transform of Kimberling's paraphrases, A003602.
19

%I #29 Nov 24 2023 12:38:16

%S 1,0,1,0,2,0,3,0,3,0,5,0,6,0,4,0,8,0,9,0,6,0,11,0,10,0,9,0,14,0,15,0,

%T 10,0,12,0,18,0,12,0,20,0,21,0,12,0,23,0,21,0,16,0,26,0,20,0,18,0,29,

%U 0,30,0,18,0,24,0,33,0,22,0,35,0,36,0,20,0,30,0,39,0,27,0,41,0,32,0,28,0,44,0,36,0,30,0,36

%N Möbius transform of Kimberling's paraphrases, A003602.

%H Antti Karttunen, <a href="/A349136/b349136.txt">Table of n, a(n) for n = 1..20000</a>

%F a(n) = Sum_{d|n} A008683(d) * A003602(n/d).

%F a(1) = 1, a(n) = A000010(n)/2 for odd n > 1, a(n) = 0 for even n.

%F For all n >= 1, a(2*n-1) = A055034(2*n-1) = A072451(n).

%F a(n) = phi(n) - (1/2)*phi(2n), for n>1. - _Ridouane Oudra_, Jul 13 2023

%F Sum_{k=1..n} a(k) ~ (1/Pi^2)*n^2. - _Amiram Eldar_, Jul 15 2023

%p with(numtheory): a:=proc(n) if n=1 then 1; elif n mod 2 = 0 then 0; else phi(n)/2; fi: end proc: seq(a(n), n=1..60); # _Ridouane Oudra_, Jul 13 2023

%t k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, MoebiusMu[#] * k[n/#] &]; Array[a, 100] (* _Amiram Eldar_, Nov 13 2021 *)

%o (PARI) A349136(n) = if(1==n,1, if(n%2, eulerphi(n)/2, 0));

%o (PARI)

%o A003602(n) = (1+(n>>valuation(n,2)))/2;

%o A349136(n) = sumdiv(n,d,moebius(d)*A003602(n/d));

%o (Python)

%o from sympy import totient

%o def A349136(n): return totient(n)+1>>1 if n&1 else 0 # _Chai Wah Wu_, Nov 24 2023

%Y Agrees with A055034 on odd arguments.

%Y Cf. A000010, A003602, A008683, A349134.

%Y Cf. A000004, A072451 (even and odd bisection).

%Y Cf. also A347233, A349127, A349137.

%K nonn

%O 1,5

%A _Antti Karttunen_, Nov 13 2021